Solar Sails - A Novel Approach To Interplanetary Travel Authors: Givanni Vulpetti, Les Johnson, Gregory L. Matloff Publisher: Praxis Publishing Ltd ISBN: 978-0387344041 Price: £16.50 (Hb), 243pp
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In the early twentieth century Swedish chemist Svante August Arrhenius suggested that solar pressure might diffuse life through the Solar System, and in the 1920s Russian scientists Konstantin Tsiolkovsky and Friedrich Arturowitsch Zander wrote that a very thin space sheet, pushed by solar-light pressure, should be able to achieve high speeds in space. Indeed, the Russians were the first to deploy a spinning solar sail in 1993 from a Progress re-supply craft to the Mir space station. Rather interestingly a solar sail mission was proposed to rendezvous with Halley's comet but the funding was not approved, although I wonder how the delicate solar sails would have coped with the cometary debris.

This is a very practical book; the authors begin with the theory of solar sails, discuss the advantages and disadvantages compared to other forms of propulsion, consider construction and design, detail the experiments that have taken place, deliberate on potential future missions, and finally delve into complex mathematics. The concept of steering and propulsion by lasers and microwaves, and even self-repairing solar sails, adds interesting possibilities.

The likelihood of a future mission appears rather stalled at present. A recently proposed NASA project failed to be approved, the Russian programme appears to be in hiatus, and in May 2006 the European Space Agency sought tenders for a three to five year mission called Geo Sail, although there seems to be little practical progress to date. The authors consider whether a private initiative will bring forth a solar sail mission, and I think there may be a good case for this. The Planetary Society's Cosmos 1 mission failed due a malfunction in the Russian launcher, but surely they will try again? Readers will certainly find the book highly informative and for anyone involved in building or considering solar sail missions, the authors' research will prove to be a valuable resource. I was left with the distinct impression that solar sails really do deserve a good test mission, and I can't wait for it to happen. Highly recommended.

Robin Flegg